1. Field of the Invention
This invention relates to a collection assembly and more particularly to a microcollection container and cap suitable for collecting small quantities of a specimen such as blood from a patient and providing access to the interior of the container without the need for removing the cap from the assembly and for maintaining a specimen in secure fashion for subsequent testing.
2. Description of Related Art
Analytical instrumentation has made it possible to carry out a variety of hematological diagnostic procedures on very small quantities of blood. Because of this, a patient""s finger or earlobe, for example, may be punctured and a very small quantity of blood may be rapidly collected into a container for such testing. Once the small quantities of blood are collected, the container is sealably covered by a cap.
In order for a laboratory technician to conduct tests on the blood sample which is collected in the container, the cap must be removed from the container so as to provide access to the blood sample. In the alternative, the entire contents of the container may be transferred from the container to an instrument compatible sample holder in order for laboratory analysis to take place.
Therefore, there is a need for a microcollection container that is (i) compatible with instruments for laboratory analysis whereby the specimen does not have to be transferred out of the container for analysis to be conducted; (ii) provides a resealable portion for easy access into the container by a needle or probe that also prevents specimen leakage out of the container, (iii) maintains a specimen in secure fashion; and (iv) prevents contamination to the specimen and to the user.
The present invention is a collection assembly comprising a container and a cap. The cap preferably comprises a top portion, a bottom portion, and an annular skirt extending from the top portion to the bottom portion having an inner surface and an outer surface. The cap further includes an inner inverted skirt portion surrounded by the inner surface of the annular skirt. Most preferably the inner inverted skirt portion is separated from the inner surface of the annular skirt by an annular space. The inner inverted skirt extends between an upper extent and a lower extent whereby the lower extent supports a septum or membrane. Desirably, the septum is a disc-like membrane formed of a self-sealing and resealing thermoplastic elastomer material.
Most preferably, the septum is capable of being pierced and resealed on a repetitive basis with a piercing element such as a needle or instrument probe. Most preferably, the septum is formed of a thermoplastic elastomer. Such thermoplastic elastomer includes isoprene propylene, such as MONOPRENE (a trademark of QST, Inc.) sold by QST, Inc., St. Albans, Vt.
Preferably, the membrane and the cap body may be co-injection molded or insert molded.
Most preferably, the cap also includes a cam follower positioned on the bottom portion. Desirably, the inside surface of the annular skirt comprises at least one protrusion and the inner inverted skirt portion has a sealing ring. The cap further comprises a rim extending from the outer surface of the annular skirt.
The container preferably comprises an open top portion, a closed bottom portion, a sidewall extending from the top portion to the bottom portion and an open end associated with the top portion having an integral collector. Most preferably, the integral collector is a scoop that is the same diameter as the inner diameter of the container so that no air vent is required.
Preferably, at least one lug is located on the outer diameter of the top portion of the container.
Preferably, the container further includes a cap seating flange associated with the outer diameter of the top portion of the container and an extending annular skirt associated with the bottom portion. Optionally, a reservoir is positioned within the cap seating flange and at least one lug is located in the reservoir. Preferably, the container also includes a locking ring associated between the integral collector and the cap seating flange.
Preferably, the collection assembly includes means for securing the inner surfaces of the cap to the top portion of the container by the interaction of the protrusions of the cap with the locking ring of the container and the sealing ring of the cap with the inside surface of the top portion of the container. Most preferably, the collection assembly also includes means for unsecuring the cap from the container by a cam arrangement on the cap and container. This cam arrangement assists in substantially reducing fluid splatter from the container when the cap is removed from the container.
In one embodiment of the invention, the cam arrangement includes at least one cam follower positioned on the bottom portion of the cap and at least one cam surface positioned on the outer diameter of the top portion of the container. A downwardly rotational force applied to the cap and an upwardly force applied to the container along the longitudinal axis, causes the cam follower and the cam surface to align and the cap to snap-seal to the container by the interaction of the protrusions of the cap with the locking ring of the container and the sealing ring of the cap with the inside surface of the top portion of the container. This action, which may cause an audible-snap, in turn seals the container by compressing the protrusions of the cap against the locking ring of the container and the sealing ring of the cap against the inside surface of the top portion of the container to form a non-permanent lock and to substantially prevent the outer surface of the top portion of the container from making contacting with the inside surface of the cap""s annular skirt.
The cap and container are then unsecured in a twist off manner by applying a rotational force to the cap. Most preferably, an upward rotational force is applied to the cap and a downwardly force applied to the container along the longitudinal axis. This causes the cam follower to rise on the cam surface and in turn the cap is unsecured from the container. An important advantage of the present invention is that the rotational force applied to the cap can be bi-directional, that is clockwise or counter-clockwise.
In another embodiment of the invention, the cam arrangement includes at least one cam follower positioned on the bottom portion of the cap and at least one cam surface positioned in the cap seating flange of the container.
The collection assembly of the present invention is preferably used in micro-centrifuges. However, an extension may be secured and unsecured to the bottom portion of the container. The extension increases the length dimension of the container. With the extension, the container may be compatible with standard clinical centrifuges.
An advantage of the present invention is that any excess fluid on the outside surface of the integral collector is directed downwardly into the cap seating flange. Therefore, radial spray of excess fluid is minimized.
Another advantage of the invention is that the cap may be secured and unsecured to the bottom portion of the container. In particular, the annular space in the cap between the annular skirt and inverted skirt allows the cap to be removably secured with the bottom portion of the container by receiving the annular skirt of the container.
Still another advantage of the invention is that the recessed inverted skirt and the sealing-ring substantially reduces cap contact with fluid collected in the container. Therefore the inner surfaces of the cap may be minimally exposed to fluid collected in the container when the cap is secured to the top portion of the container.
Another advantage of the present invention is that the outer surface of the cap may preferably be configured to substantially limit movement or rolling of the cap or the assembly. This applies whether the cap is positioned with the top portion or bottom portion of the container.
Still another advantage of the present invention is that when the cap is secured to the container, the rim of the cap substantially prevents contamination to the specimen inside the container.
An advantage of the present invention is that it facilitates direct access to a sample or diagnostic instrumentation systems and enables microcollection tube compatibility with diagnostic instrumentation by providing features such as pierceability and self-resealing of the cap.
Still another advantage of the present invention is that the self-sealing pierceable cap permits mixing of the specimen in the container without transferring the specimen to another container and providing for direct access to the specimen via the self-sealing pierceable cap by diagnostic instrumentation.
Most notably, is that the present invention permits a specimen to be accessed through the top of the cap without removing the cap from the container, thereby providing minimal exposure of the specimen to the user.
In addition, the present invention permits the assembly to be directly used on instrumentation similar to that used for evacuated collection assemblies.
Advantages of the membrane of the present invention include that: (i) it can be pierced and resealed many times; (ii) it requires less than 2 lb. Force for a piercing element to pierce it; and (iii) the concave shape aids in the ability of the membrane to seal properly after the piercing element is removed.